The present invention relates to a paper discharge base of an image forming apparatus such as a copying apparatus or a printing apparatus for retaining a print sheet discharged from a printing section of an image forming apparatus in a stacked state.
With high speed formation of an image forming apparatus such as a copying apparatus or a printing apparatus in recent years, a print sheet discharged from a printing section thereof is discharged at high speed toward a paper discharge base and is impacted to an impact wall of the paper discharge base with large momentum. In this case, when the impact wall is of a rigid structure, there is a drawback that a large impact sound is emitted in impacting the print sheet.
Hence, there is disclosed a paper discharge base for alleviating an impact sound of a print sheet in Japanese Patent Laid-Open No. 183553/1997. Such a paper discharge base is provided with a paper mounting floor and an impact wall. The main body of the impact wall is attached with an impact wall plate impacted by a print sheet via an elastic film. Therefore, according to the paper discharge base, impact force when a print sheet is impacted to the impact wall plate is damped by the elastic film and the impact sound is alleviated.
However, the impact wall plate impacted by a print sheet is made of foamed styrene or foamed polyvinyl chloride. Since the print sheet is directly impacted to the impact wall plate at high speed, there is a drawback that the impact wall plate is gradually impaired by the impact force after long hours of use.
Further, since the impact wall of the paper discharge base needs a mechanism of expanding the elastic film, there also is a drawback that the structure of the impact wall becomes complicated.
Further, depending on paper quality of a print sheet, when a print sheet is not impacted to an optimum position of the impact wall plate, the print sheet loaded on the paper mounting floor does not align neatly.
Further, the height of a print sheet impacted to the impact wall plate differs by paper quality (weight) of a print sheet. In case of a heavy print sheet, the height of impact is low and in case of a light print sheet, the height of impact becomes high.
Therefore according to the paper discharge base disclosed in the publication, a print sheet is not impacted to an optimum position of the impact wall plate depending on the paper quality of the print sheet owing to a difference in the height of impact caused by the paper quality (weight) of the print sheet as described above. Therefore, there is a drawback that the impact cannot be damped effectively.
The present invention has been carried out in order to resolve the above-described drawbacks of the conventional technology. It is an object thereof to effectively damp impact of a print sheet discharged from a printing section. Particularly, it is an object thereof to promote durability against impact of a print sheet.
Further, it is another object thereof to further promote strength of a surface of a damping member and damping operation of the damping member. Further, it is an object thereof to smoothly drop a print sheet along the surface of the damping member in accordance with property of the surface.
Further, it is another object thereof to excellently align a print sheet which is impacted to a damping member and drops.
It is still another object thereof to alleviate impact sound of a print sheet and spring back of the print sheet caused by impact.
Further, it is another object thereof to gradually reduce kinetic energy of a print sheet impacted to a surface of a damping member. Further, it is an object thereof to effectively prevent spring back of a print sheet caused by a damping member thereby.
It is still another object thereof to achieve further sound pacifying formation of an impact sound of a print sheet by a simple constitution. Further, it is an object thereof to further alleviate spring back of a print sheet caused by impact and excellently align a sheet.
Particularly, it is an object thereof to make a damping member further easy to escape in the direction of discharging a print sheet (space portion side) and drop a print sheet impacted to a damping member further in a constant direction along a surface of the damping member.
Further, it is another object thereof to dispose a damping member at a position capable of damping effectively an impact of a print sheet in correspondence with a paper quality of the print sheet.
It is still another object thereof to be capable of adjusting a position of the damping member such that the impact of the print sheet can effectively be damped in correspondence with the paper quality of the print sheet.
In order to achieve the above-described object, according to the first aspect of the present invention, there is provided a paper discharge base of an image forming apparatus including an impact wall 70 impacted by print sheet P discharged from a printing section,
a damping member 78 provided at an impact position of the impact wall 70, and
a paper mounting floor 72 loaded with the print sheet P which is impacted to the damping member 78 and drops,
wherein the damping member 78 is constituted by a sponge sheet 84 and a protection sheet 86 attached to a surface of the sponge sheet 84 impacted by the print sheet P.
According to the first aspect of the present invention, when the print sheet P is impacted to the damping member 78, the impact force is transmitted from the protection sheet 86 to the sponge sheet 84 and is damped by the sponge sheet 84. Further, the impact sound is alleviated. The sponge sheet 84 is protected by the protection sheet 86 and accordingly, durability against impact of the print sheet P is promoted.
According to the second aspect of the present invention, there is provided the paper discharge base according to the paper discharge base of an image forming apparatus of the first aspect, in which the protection sheet 86 of the damping member 78 is made of polyethylene terephthalate.
According to the second aspect, by applying a film made of polyethylene terephthalate having high strength, damping operation of the sponge sheet 84 is promoted by thinning the protection sheet 86 and the sponge sheet is protected sufficiently against the impact force of the print sheet P. Further, the film made of polyethylene terephthalate is provided with a property in which a surface thereof is smooth. Therefore, the print sheet P impacted to the protection sheet 86 is made to drop smoothly along the surface of the protection sheet 86.
According to the third aspect of the present invention, there is provided the paper discharge base of an image forming apparatus according to the paper discharge base of an image forming apparatus of the first or the second aspect, further including regulating faces 80 projected from a portion of the damping member 78 on a lower side of an impact position thereof to a side of an apparatus main body 14 on both sides of the impact wall 70 formed on the lower side of the impact position at which the print sheet P is impacted to the damping member 78 for leading a front end edge portion of the dropping print sheet P to the lower side while being brought into sliding contact therewith.
According to the third aspect, the print sheet P impacted to the surface of the damping member 78 drops by its own weight. The print sheet drops slidingly in a state in which the front end edge portion is being brought into contact with the surface of the damping member 78. Further, when the print sheet P slidingly drops to a position of a lower end portion 78B of the damping member 78, both ends of the front end edge portion of the print sheet P are brought into sliding contact with the regulating faces 80. Further, the print sheet P is successively stacked on the paper mounting floor 72 in a state in which the front end edge portion is aligned and contained.
According to the fourth aspect of the present invention, there is provided the paper discharge base of an image forming apparatus according to the paper discharge base of an image forming apparatus according to any one of the first through the third aspects, in which the damping member 78 includes a space portion 92 on a rear face side of the impact position of the print sheet P.
According to the four the aspect of the present invention, when the print sheet P is impacted to the damping member 78, by the impact force, the damping member 78 is elastically deformed to escape in a direction of discharging the print sheet P constituting a side of the space portion 92. Thereby, both of the impact sound of the print sheet P and spring back of the print sheet P caused by impact are alleviated.
According to the fifth aspect of the present invention, there is provided the paper discharge base of an image forming apparatus according to the paper discharge base of an image forming apparatus of the fourth aspect, in which the lower end portion 78B of the damping member 78 is provided in the direction of discharging the print sheet P relative to an upper end portion 78A of the damping member 78.
According to the fifth aspect of the present invention, a surface of the damping member 78 is formed in a shape of a gradually curved face inclined in the direction of discharging the print sheet P gradually from the upper end portion 78A to the lower end portion 78B. The print sheet P impacted to the surface of the damping member 78 drops along the curved face of the damping plate 78 while being directed to the discharge direction along the curved surface of the damping plate 78, that is, while kinetic energy of the print sheet P is being gradually reduced and led to the regulating portions 80. The print sheet p is smoothly stacked onto the paper mounting floor 72 by preventing spring back caused by the damping plate 78.
According to the sixth aspect of the present invention, there is provided the paper discharge base of am image forming apparatus according to the paper discharge base of an image forming apparatus according to the fifth aspect, in which either one of the upper end portion 78A and the lower end portion 78B of the damping member 78 is fixed to a side of the impact wall 70 and the other thereof is held slidably in up and down directions relative to the side of the impact wall 70.
According to the sixth aspect of the present invention, in case the upper end portion 78A (lower end portion 78B) is fixed, when the print sheet P is impacted to the damping member 78, the damping member 78 is elastically deformed in the discharge direction and the lower end portion 78B (upper end portion 78A) is lifted (lowered). Thereby, the damping plate 78 becomes easy to escape in the direction of discharging the print sheet P constituting the side of the space portion 92. Further, the position of the lower end portion 78B (upper end portion 78A) of the damping plate 78 is held by a receive portion 88B and accordingly, the print sheet P impacted to the damping plate 78 drops in a constant direction along the surface of the damping member 78.
According to the seventh aspect of the present invention, there is provided the paper discharge base of an image forming apparatus according to the paper discharge base of an image forming apparatus of any one of the fourth through the sixth aspects, further including position adjusting means 94 provided at the impact wall 70 and capable of adjusting the position of the damping member 78 in the up and down directions.
According to the seventh aspect of the present invention, the damping member 78 is freely disposed at a position of effectively damping impact of the print sheet P in correspondence with paper quality of the print sheet P.
According to the eighth aspect of the present invention, there is provided the paper discharge base of an image forming apparatus according to the paper discharge base of an image forming apparatus of the seventh aspect, in which the position adjusting means 94 includes a click mechanism for positioning the position of the damping member 78 in the up and down directions to a predetermined position.
According to the eighth aspect of the present invention, the damping member 78 is freely positioned to a position of effectively damping impact of the print sheet P in correspondence with a paper quality of the print sheet P having a predetermined paper quality.